An air conditioner for automobiles typically refers to a device in which outside air introduced by a fan undergoes heat exchange by being selectively passed through an evaporator through which refrigerant flows or a heater core through which engine cooling water flows, after which the air is ventilated through openings communicating with various areas within the passenger compartment to thereby cool or heat the passenger compartment. Such an air conditioner includes a cylindrical mode door for selectively supplying the heat exchanged air to various areas within the passenger compartments.
A structure of a conventional air conditioning system for automobiles will be described hereinafter with reference to FIGS. 1 through 5.
First, as shown in FIG. 1, a fan 101 is mounted within an air conditioning case 100, and outside air is drawn into the air conditioning case 100 through an air inlet port (not shown) of the air conditioning case 100 by the fan 101 and is ventilated in the direction of the arrow S.
A front opening 104, a floor opening 105, and a defrost opening 106 are formed in the air conditioning case 100 to enable air to be discharged into various areas of the passenger compartment after the air is supplied to inside the air conditioning case 100 and selectively passed through an evaporator 102 or a heater core 103 to undergo cooling or heating. The openings 104, 105, and 106 are uniformly formed adjacent to one another in a rotational direction of a cylindrical door 107, which will be described below.
The front opening 104 is an opening for discharging air toward the upper half of passengers' bodies, while the floor opening 105 is an opening for discharging air toward the lower half of passengers' bodies. The defrost opening 106 is an opening for discharging air toward the inside of the front windshield to remove frost therefrom.
The cylindrical door 107 is a mode door that adjusts an opening area of the openings 104, 105, and 106 depending on the fan mode. The cylindrical door 107 is rotatably mounted in the air conditioning case 100.
The cylindrical door 107, with reference to FIG. 2, includes a rotating door 108 and a film member 109. The rotating door 108 includes semicircular side walls 110 and a main wall 11 in the shape of a circular arc. A rotating shaft 108a is formed in each of the side walls 110. Each of the rotating shafts 108a is positioned substantially in a center of a curvature of the main wall 111 and is protruded outwardly along an axial direction. Although the side walls 110 are described as being semicircular, they may also be circular.
The main wall 111 includes four apertures 111a formed in the axial direction and substantially uniformly spaced apart from one another in the circumferential direction thereof.
The film member 109 is flexible and does not allow the passage of air therethrough. Also, the film member 109 has an overall quadrilateral shape with a width that is almost identical to a dimension of the main wall 111 of the rotating door 108 in the axial direction. Ventilation openings 109a are formed in the film member 109 in a lengthwise direction thereof.
The remaining elements shown in FIG. 2 are those used to mount the film member 109 on the rotating door 108, and so a detailed description thereof will be omitted.
The process of changing the fan mode by operation of the cylindrical door 107 will now be briefly described with reference to FIG. 3.
First in a front mode, the cylindrical door 107 is rotated such that only the front opening 104 is open, while the remaining openings 105 and 106 are closed. As a result, air introduced into the air conditioning case 100 by operation of the fan 101 passes through the apertures 111a of the cylindrical door 107 and through the ventilation openings 109a of the film member 109 to pass through the front opening 104 to be discharged into the passenger compartment (air flow I). The film member 109 expands in a circumferential direction by air pressure such that the film member 109 is pressed firmly against circumferential edges 112 and 113 of the front opening 104 to prevent gaps from being formed between these elements. Therefore, air does not leak in this area of the circumferential edges 112 and 113, and is discharged through the front opening 104 only.
When desiring to change to a fan mode in which the openings 105 and 106 are opened, the cylindrical door 107 is rotated to thereby alter the positioning of the apertures 111a of the cylindrical door 107.
As described above, the leakage of air between the main wall 111 of the cylindrical door 107 and an inner surface of the air conditioning case 100 is prevented by expansion of the film member 109.
Referring to FIG. 4, a gap between both of the side walls 110 of the cylindrical door 107 and the inner surface of the air conditioning case 100 is sealed using a sealing member 120 to thereby prevent the leakage of air through this gap.
However, in the conventional air conditioning system for automobiles described above, friction is generated between the sealing member 120 and the inner surface of the air conditioning case 100 when the cylindrical door 107 is rotated. This, in turn, causes the generation of noise. In addition, it is necessary to perform an additional sealing process during production of the cylindrical door 107 such that costs associated with the manufacture of the air conditioning case 100 are increased and assembly of the cylindrical door 107 and the air conditioning case is made complicated.
In modern air conditioning systems for automobiles, the front opening is divided into a center opening and two side openings formed to opposite sides of the center opening, and a function is provided such that air introduced into the air conditioning case is continuously discharged to both sides of the passenger compartment through the side openings.
FIG. 5 is a plan view of an air conditioning system (when viewed from above) having such a continuous discharge function.
In the air conditioning system of FIG. 5, side openings 214 are formed to opposite sides of a center opening 204 that is positioned to an upper area of an air conditioning case 200. Constant discharge openings 207a are formed in the vicinity of both ends of a cylindrical door 207 mounted within the air conditioning case 200, and an aperture 207b is formed in a lengthwise direction of the cylindrical door 207. In the air conditioning system structured in this manner, air is always discharged through side openings 214 via the constant discharge openings 207a of the cylindrical door 207 even when not in a defrost mode (for removal of frost) such that frost generated on the front windshield may be removed.
That is, in the case of the front mode with reference to FIG. 5a, the aperture 207b of the cylindrical door 207 communicates with the center opening 204, and the constant discharge openings 207a of the cylindrical door 207 communicate with the side openings 214. In the case of the defrost mode with reference to FIG. 5b, the aperture 207b of the cylindrical door 207 communicates with a defrost opening 206, and the constant discharge openings 207a of the cylindrical door 207 communicates with the side openings 214 as when in the front mode.
A constant discharge opening cover 220 that covers the constant discharge opening 207a of the cylindrical door 207 is mounted to one side of the defrost opening 206. This prevents air from being discharged through the defrost opening 206 via the constant discharge openings 207a while in the front mode, and hence reducing the amount of air that is discharged toward the front of the passenger compartment. That is, in the above conventional air conditioning system for automobiles, in a mode other than the defrost mode (e.g., the front mode or floor mode), air is prevented from being discharged through the defrost opening 206 through the constant discharge holes 207a of the cylindrical door 207.
However, with the above structure of the conventional air conditioning system for automobiles, the above function is realized by merely reducing a size of the defrost opening 206. As a result, the amount of air used to remove frost in the defrost mode is significantly reduced.